No.34630
作者：nust10
邮件：
ID：2056
登陆：2次
文章数：2篇
最后登陆IP：218.2.137.59
最后登陆：2003/6/20 9:12:18
注册：2002/5/9 10:36:00
财富：12
发帖时间：2003/6/16 22:18:18
发贴者IP：218.2.137.41
标题：nust10:80c196kb 的奇怪现象,谢谢 !
摘要：No.3463080c196kb 的奇怪现象,谢谢 ! he CPU I use is 80c196KB 16, 8 bit data bus.
My problem is about writing an value to a memory-mapped I/O. I define as the following:
#define SBAUD 0xc0a
1. I write this code:
*(unsigned char *)SBAUD=0x08;
It does'twork. The value in I/O 0xc0a is 0x00,not 0x08. 2. I write this code two times:
*(unsigned char *)SBAUD=0x08;
*(unsigned char *)SBAUD=0x08;
It can work. The value in I/O 0xc0a is 0x08. 3. If I write this code:
*(unsigned char *)SBAUD=0x08;
*(unsigned char *)SBAUD=0x08;
*(unsigned char *)SBAUD=0x09;
It works wrong. The value in I/O 0xc0a is 0x08,not 0x09. 4. If I write this code:
*(unsigned char *)SBAUD=0x08;
*(unsigned char *)SBAUD=0x08;
*(unsigned char *)SBAUD=0x09;
*(unsigned char *)SBAUD=0x09;
It works well. The ......
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